Qc Universal Light Crossbar - 4 Inches Light Fixture Mounting Bracket with Ground Screw and Acorn Cap Nuts for Mount Wall Light, Close to Ceiling Light (2 Pack) - Amazon.com
21pcs/Sets Universal Light Fixture Mounting Bracket 4 Inch Wall Lamp Installation Bracket Crossbar Ceiling Fan For Home Garden - AliExpress
Ceiling Light Fixture Mounting Bracket with 4 Inches Diameter Universal Light Crossbar, Steel Crossbar Plate for Mount Wall Light, Close to Ceiling Light, Chandelier - Pack of 2 - Amazon.com
Project Source 4-in Silver Metal Ceiling Light Mount in the Ceiling Light Mounts department at Lowes.com